1. Field of the Invention
This invention relates to an improved, counter-rotating trolley and track suspension system for supporting an operable wall panel. The trolley and track suspension system is self-plumbing so that if there is any misalignment along the axial center line of the suspension system, the trolley assembly will always be in mating contact with the corresponding rails of the track.
2. Prior Art
Various designs of trolley and track assemblies of the counter-rotating type are known. In U.S. Pat. No. 3,042,960, a counter-rotating trolley and track assembly is disclosed. However, the rails of the track and the contacting surfaces of the rotating discs are in the horizontal plane so that any misalignment between the trolley and track assembly along its axial center line will cause one of the discs to shift away from mating contact with its corresponding rail, thereby placing the entire load on the other disc. In U.S. Pat. No. 3,879,799, a multidirectional, self-centering, suspension system is disclosed. Both the rotating discs of the trolley and the corresponding track rails are formed having frusto-conical cone surfaces so that the counter-rotating discs will always be centered. However, should there be any misalignment relative to the track and trolley assemblies along its axial center line, one of the discs will be shifted away from the corresponding track surface, causing the entire load to be shifted to the other rotating disc. In U.S. Pat. No. 4,141,106, a canted wheel carrier for supporting an operable wall is disclosed. The canted wheel assembly is arranged and constructed to negotiate angle turns or intersections without the necessity for using switching devices or curved supporting surfaces. The assembly is not self-plumbing so that any misalignment between the track and wheel carrier would cause the load to be shifted to a single wheel. U.S. Pat. No. 4,159,556 discloses a suspension system which is capable of moving along a track and negotiating a junction, such as an intersection, without dislodgment of the trolley from the track. The trolley and track assembly is not self-plumbing since any misalignment of the trolley with respect to the track along its axial center line would cause contact of the supporting plates of the trolley with the interior surfaces of the track.